Cell phoner and Airplanes

Yes they can.
If youre at an altitude of 10,000 feet or below and your cell phone is active (such as making or receiving a call or using internet data services) it can interrupt the navigation and communication controls to a certain extent. Many of todays airplanes have a GPS terrain navigation system and radar mapping on the flight deck but of course those are prone to interference, specially at 10,000 feet and below.

Why 10k feet?
Well, after 10k feet aircraft reach cruising altitude and a lot of the planes fly automatically after the 10k ft have been reached but on take off and landing pilots have to do a lot of the manual work and really concentrate on whats going on in there and a radio interference problem is certainly something they dont want.

a lot of new phones are coming out with this feature called "Airplane mode" that disables phone to tower transmissions so you can still fiddle with other features of your phone. such as games or any other annoying beeping thing. Chances are, with the current insulation of aircraft and all that wiring, you wont even get a signal in a plane once the main doors have been closed.

So dont believe what reports say that people called from their cell phones while on the planes that were hijacked on Sep 11 2001, its a conspiracy. (IMO)

Anyway, have fun traveling on airplanes and dont bother the friendly Flight Attendants.

Love,
Former Flight Attendant - Cop-

 

Yeah JetBlue seems to be a bunch of nice folks.
Happy flying.

 

I fly 2 round-trips a year and a couple years ago I tried one of those Cricket phones. I was over, let's say Tennessee, and I had 3 bars on my phone at 41,000 ft. Oh, and this was a Nokia 5170i. I even tried making a call (dont tell the FAA ) but it was dropped after about 15 seconds. Then I turned it off. Weird... lol

 

Cop wrote:Why 10k feet?
Well, after 10k feet aircraft reach cruising altitude and a lot of the planes fly automatically after the 10k ft have been reached but on take off and landing pilots have to do a lot of the manual work and really concentrate on whats going on in there and a radio interference problem is certainly something they dont want.
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Reply:
Been flying since 1974, never heard that, 10K foot thing. But the gist is OK, I guess.

Many airlines have tested this theory with no confirmation of interference, British airways (I think) tests found some scenarios possible. United says fell free to use it on the ground.

The FCC, on the other hand does not want a transmitter up high, confusing cell sites which may lock on to your signal. As you know cell sites are close together to cover a relatively small area on the ground. A radio (cell Phone) up high can in theory, lock on to more than one site and cause havoc, for a moment.

The conspiracy people say that the airlines just want us to use the sky phones at $1.99 a minute or more, perhaps

Can it interfere with Navigation equipment, I doubt it (for the most part).
WHY? Glad you asked; All of the antennas for GPS, VOR, Radar, Coms and sky phones are on the outside, NOT ON THE INSIDE where your cell phone is.
The new large transports use lots of shielded cable and fiber optics, impervious to low power rf.

Your only chance of getting your max of 200 mw (digital) out of a large jet is through the Plexiglas window.

The best reason I can think of to tell people not to use a cell phone, in flight, is to keep loud jerks quiet. Especially, Nextel speaker phone users; BEEP!
Imagine that from PHL or JFK to LAX or SFO; 5 hours of BEEP. BEEP, BEEP!!!!

 

In the past, I've been annoyed that I wasn't "allowed" to use my mobile in a plane, but your comment about loud jerks converted me! I will forgo the convenience in exchange for at least some relative peace and quiet. Now about restricting mobiles in restaurants....

 

And movie theaters.

 

dee1jay:WROTE:
In the past, I've been annoyed that I wasn't "allowed" to use my mobile in a plane, but your comment about loud jerks converted me! I will forgo the convenience in exchange
_____________________________________________________________________________

REPLY:
I was just trying to explain the AIRPLANE thing from a passengers and pilots prospective.

As to the other comment; Its not just airplanes where people seem to BROADCAST.
Loud jerks don't seem to mind blasting their business in all kinds of places.

That said; I use my phone almost everywhere, I just try to speak in a lower volume and try to be polite.

KEEP TALKING, just not at altitude.

 

Okay, let's see if we can clear this up. There is a company called AirCell that has had AMPS telephones installed in Business and General Aviation planes for over 5 years now. This system is analog, and cannot be accesed by normal ground customers. These business jets fly at over 45,000 feet sometimes. There has never been one documented case of interference between use of the AirCell system, and any navigational or communication system on board any aircraft. If you are in the right place, you can very easily use your terrestrial mobile phone in the air. The limiting factors are speed (doppler effect), and distance to cell. Customers who use their phones in the air DO create interference on the ground, and because of speed, create interference across multiple sites in a short amount of time. Imagine one damaged phone travelling through the wireless system at 500 knots plus! The FCC and FAA do not want you to use your phone in an unapproved manner specifically because of the interference created. It has nothing to do with navigation systems or communications.

 

The use of RF generating devices ARE prohibited by FAA regulations on commercial aircraft, without the pilot's permission. There IS the remote possibility of interference to the aircraft navigational system. For instance, even using an FM broadcast reciever (FM radio walkman, boom box, etc) can pose a threat. Here's how: all radio recievers have what is called an IF stage which is where the audio signal is seperated from the RF, it actually radiates a small amount of RF itself by operation, and with FM radios, it is usually at 10.7 MHz above the tuned frequency. So say, if you are listening to a radio station on 104.1MHz and your FM radio is putting out an oscillation at 10.7MHz above, you are placing a carrier (albeit low power) on 114.8MHz, smack in the middle of the VHF aircraft NAV band! (aircraft voice and NAV radios are VHF AM from 108-136MHz). You could theoretically disrupt operations. and on a plane, you can't just "pull over" to isolate the problem.

All transmitters put out spurs (unwanted signals) that can cause problems to some equipment. It is more the case with better safe than sorry, and I agree. I certainly think it better to be cautios than allow unfettered use of RF generating devices on planes. Even laptops and CD players have been cited as generating stray RF in the aircraft band. Aircraft safety isn't something to play around with.

Besides, using modern digital phones is useless at that altitude anyway. The networks were designed to be terrestrial mobile (ground) and you get all kinds of multipath and overload from the myriad of sites that your phone can "see" at 35,000 feet. CDMA systems are practically useless, as the signals from all the sites on the same frequency are of equal stregnth and thus cancel each other out at your phone's reciever.

And for those of you curious about the GTE/Verizon AIRPHONES, they use a 900MHz TDMA based system with satellite capability (for outside the US). The base stations are arranged in a cellular configuration, but spaced out much further and in fewer places. Too bad they don't cut us Verizon customers a break and allow us "included useage" when flying! America's choice goes to the air!

 

XprtCop, you can choose not to believe it, but I know for a fact and by first hand experience that this is possible, especially since the hijacked planes were flying very low, the signals were easy to pick up from the planes.

 

FYI the AirCell phones aboard general aviation and private jets are TYPE ACCEPTED for each plane, and certified by the FAA....

Also, one other misnomer, CDMA DOES work at 35,000 feet....the only limiting factor is the timing delay that results in the improper extraction of the Short PN code of the cell site.......Which, if you *wink* were designing a system for use in the air, can be overcome by the use of Psuedo or fake PN's that the phone sees based on the timing delay. Couple that with a concentric ring approach to the base station that has progressively longer timing delays the further from the cell.....This compensates for PN's appearing outside the window....gee...don't have any clue why I might know that........Oh yeah, it came to me in a dream.....

 

SNSE,WROTE : Tip and Ring has nothing to do with a waiter bringing you the phone...


REPLY

GEE: red green yellow black?

You may recall the "old" 450 MHz duplex system
which any scanner could hear at least one side of. That was still on as of a year ago or so.


On SUBJECT:
RECALL 911 when it is said that passengers did use cell phones to call out, i.e., Barbara Olson calling her husband Ted Olson, the US Solicitor General., He recounted that she kept getting cut off and called him back, so they work.
Not always well.

 

Blue Orange Green Brown Slate (Bell Operators Give Better Service) and groups of White Red Black Yellow Violet......Outside plant and interconnect....House wire of Red Green Yellow Black......Good thing I wasn't color blind........

Too bad they don't make any of these young'ens lace much these days.......

Now, let's see who's who....Loop Start, Ground Start , E&M 4 wire, E&M 6 wire, lost anybody yet? Line concentrators,
ringdown conference circuits....whoa take me back......DMS-10 remote switches....

Oh sorry, I must have been rambling......

 

I still have a DYNATEL charged up and working

 

Yep.....we may be getting off topic now........

 

OK SO: what works better from inside an airliner (Not slower GA planes)
TDMA, GSM or CDMA.

Anyone ever try IRADIUM; sitting next to a window , aloft?

 

Short answer, none of them work well without some kind of external antenna. There would be extensive software changes that would have to be made to the ground station to compensate for speed and distance, plus other issues. There are many Iridium systems in Learjets that go as fast as an airliner, that work just fine, however, there is an external "patch" antenna installed on the top of the fuselage. As far as mobile service inside the cabin, that may very well happen. And, we'll have the issue of the last safe area away from ringing phones being sacred no more........

 

I promise you, you can get coverage in an airplane, Cop. I usually do a round trip a week and on a couple of occasions I (and others) have forgotten to turn off our phones... midway through the flight you might hear a ring or a message notification.

Signals don't just travel parallel to the ground, you know.

Also, Southwest have started allowing phones to be used as soon as the plane is off the main runway on landing. I don't like this development because it means I have to listen to all the loud self-important salespeople ("BERNIE! I'VE BEEN IN AN AIRPLANE FOR THE LAST 45 MINUTES, WHAT HAPPENED SINCE THEN?!")...

Honestly... if you can't be out of contact for 45 minutes, either change your flight, take the train, or drive...

The only nice part about being able to use the phone on taxi is calling the valet booth and actually having one's car ready and waiting...

 

I agree. Phones will have signal on board planes as long as you are close enough to shore. I have forgotten several times to turn off the phones.

My CDMA phone never interferes with my GPS. I do not think that my GSM phones interefere, although I did have a breif false location walking back to my apartment in Taiwan. Chances are likely that it was a refelected signal, or signal(s) rather than the phone, since it returned to the correct location after a few seconds and the phone was still on my hip in standby.

 

Using a cellphone on an airplane can and did affect a flight I was on one time. How did I know? Well they told us that some equipment was acting up during the flight, most likely because of a phone (BTW they were telling us this while taxiing to the gate). The funny thing is right after they told us someone's phone rang and it turned-out he never turned it off and what messed with the equipment was him receiving a text message.

 

Gideon0489 wrote:
How did I know? Well they told us that some equipment was acting up during the flight, most likely because of a phone

Reply"

Respectfully you really only know what "they told you", right?

Did "they" tell you what was interfered with. Not the coffee pot I hope.

All sarcasm aside; I sit right in front of the instruments and have yet to see a glitch.

Next time, before you board, see if one of the flight crew is calling home, while loading data into the computers. That should be telling.

 

Lol good point Jerro. But this only happened to me once. I'm flying again right after Christmas so I'll take note of my surroundings .

 

For local calls just deposit ground.

 

I have turned on my 4400 while crusing at FL410 in our Citation II over the eastern seaboard, and the phone said it had a signal. While I have not tried making calls nor have I recieved one (the aircraft has AirCell installed) I doubt that it would greatly interfere with the NAV/COMMs on the plane, let alone the GPS or FMS.

It would have to interfere with communications on the ground, as far as I can see the guidance systems of the aircraft or the NAV/COMM radios are not affected.

 

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I agree, I never saw a problem with interference.
Also; I doubt that at FL410 and .85 that the 200 mw digital output will hold a signal even if it is showing that it hears the cell site. I can see it working at low altitude and low speeds.

Of course the Air Cell has an outside antenna too.

 

Very true, perhaps it was getting a ghost signal (if there is such a thing).

Only time I have actually used my phone up front was to pickup an IFR clearance when we couldn't get ATC on the Comms from the ground, no surprise it worked then. Now if only there were a way to make the fuselage act as a giant antenna..hmm

 

axvx8xoxr wrote: Very true, perhaps it was getting a ghost signal (if there is such a thing).

Only time I have actually used my phone up front was to pickup an IFR clearance when we couldn't get ATC on the Comms from the ground, no surprise it worked then. Now if only there were a way to make the fuselage act as a giant antenna..hmm

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As to a ghost signal, think of it this way, often on the comms you may be able to hear ATC before they can hear, you same for getting a reliable VOR signal. With a cell site the site is kicking out much more power that the hand set so the handset (receiver side) hears the cell site but the transmit side cant go the distance to respond. There are exceptions, when like low and slow.
At approach speeds for your aircraft.

I bet many SEL and MEL non turbine GA pilots and passengers and especially helicopters people use cell phones often. I dont but in a pinch I would.